Self-locking bushing



SELF-LOCKING BUSHING Filed June 6, 1945 FIG/ INVENTOR.

. FERDINAND KLUMPP, JR.

zen g Patented July 29, 1947 UNITED s ATEs PATENT OFFICE 6 Claims.

This invention relates to a self-locking bushing which is especially adapted for use in supporting and protecting electrical conductors that pass through plates or other metal members. For this purpose it has heretofore been the general practice to utilize grommets of soft insulating material such as rubber. It is not always easy to install these prior art devices and in pulling the electrical wire or cable through the grommet they are apt to be pulled out of the plate, or if they set loosely in the hole in which they are installed they are apt to move out, if the structure on which they are installed is subject to vibration. I

It is therefore the principal object of my invention to provide a self-locking bushing of relatively hard and tough insulating material which may be quickly installed in place and which will automatically lock itself in position and stay locked While the conductor or cable is being directed therethrough or when the device is subject to vibrations.

Another object of my invention is to provide an electrical bushing which will automatically accommodate itself to plates or structures of different thicknesses. Other advantages will be understood by those familiar with devices of this kind after a study of the following specification taken in connection with the annexed drawing, wherein:

Figure 1 is a plan view on an enlarged scale of the bushing.

Figure 2 is a part sectional and part elevational View of the device.

Figure 3 is a view of Figure 2 looking from right to left.

Figure 4 is a sectional view through the device as installed in a plate or other member with a portion of an electrical conductor or cable in position within the bushing.

In the different figures I is the body of the bushing which is, made of strong and tough insulating material. The body I terminates at one end in an annular collar or flange 2. Intermediate the flange 2 and at the opposite end of the body I there is located one or more, two being illustrated, fingers 3 which extend from their base portions 4 in an upwardly slanting direction toward the flange 2. The fingers 3 are located over the slots 5 which are positioned in flat portions 6 in the body I. The fingers terminate in somewhat enlarged ends having a plurality of steps or shoulders, three being illustrated and numbered I, 8, and 9. The purpose of these shoulders is to accommodate the bushing to plates 5 For a thicker plate I0 the shoulders 8 or 9 would come into engagement with the surface of the plate I!) on the opposite side from the flange 2.

It is to be understood that the fingers 3 at their base portions 4 have some resilience or flexi- 10 bility whereby when the bushing is pushed through a hole II in the plate or member I0 the fingers 3, which are normally positioned on an incline as indicated in Figures 2 and 4, are forced inwardly toward the axis of the bushing l5 until the bushing flange 2 encounters the outer surface of the plate or member II] when the fingers 3 will snap back so that one of the shoulders I, 8, or 9 will engage plate or member In and lock the bushing in secure position thereon.

After the bushing has been installed as above described then the conductor or cable C may be drawn through the bushing without pulling it out of place if there is any frictional engagement between the conductor or cable C and the bushing. It will be noted from the construction described that the bushing I automatically locks itself in position on a plate or member I0 and that strains on the conductor or cable or vibrations will not displace the bushing from its supporting member.

What I claim is:

1. A self-locking integral bushing of suitable insulating material, the bushing having a body portion terminating at one end in a circular flange, the body portion having at least one exterior flat surface positioned between the flange and the opposite end of the bushing, the flat surface having a longitudinally positioned slot therethrough' and an integral finger having its 40 base in the body portion and extending toward the flange over said slot, the finger in idle positing extending above the body but adapted to be moved toward the axis of the bushing when the bushing is inserted into a hole in a plate and provided at its free end with a plurality of locking means for engaging plates of various thickness within limits on the opposite side from the flange when the bushing is pushed into place in a plate.

2. A self-locking integral bushing of suitable insulating material, the bushing having a body portion terminating at one end in a circular flange, the body portion having at least one exterior flat surface positioned between the flange and the opposite end of the bushing, the flat surface having a longitudinally positioned slot therethrough and an integral finger having its base in the body portion and adapted to be flexed at the base only, the finger extending toward the flange over the slot and normally rising a substantial distance above said flat surface and the body whereby when the bushing is pushed into a hole in a mounting plate up to and against said flange, the finger will be depressed against its outwardly acting tension and plural means on the finger at its free end for engaging the plates of different thicknesses on the side opposite the flange to lock the bushing securely onto the plate.

3. A self-locking integral bushing of suitable insulating material, the bushing having a body portion terminating at one end in a circular flange and at the other end in a base portion, the body portion having a plurality of flat surfaces on the exterior part of the body, each of said surfaces having a longitudinally positioned slot therethrough, an integral finger positioned over each slot, the fingers being attached to the base portion adjacent one end of its flat surface and being bendable on said base portion, the fingers in idle position extending from said base portion in a slanting position and provided at the free ends with plural means for engaging plates of different thicknesses on the side opposite said flange when the bushing is pushed into a hole in the plate.

4. An integral bushing as set forth in claim 3 further characterized in that said plural means comprise shoulders arranged in step formation away from the free ends to cooperate with the flange to accommodate itself for looking to plates of different thickness.

5. The combination of a mounting plate having a hole therein to receive an integral bushing adapted to support and insulate a cable and a non-split bushing of tough insulating material, the bushing having a flange to engage the plate on one side and an integral finger free at one end adjacent the flange and movable about its base toward the axis of the bushing when the bushing is forced into a hole in said plate. the finger having a plurality of shoulders at least one of which is brought by the resilience of the finger into locking engagement with the side of the plate opposite to that engaged by said flange when the bushing is forced into the hole in the plate up to said flange.

6. The combination of a mounting plate having a hole therein to receive an integral bushing adapted to support and insulate a cable and a non-split bushing of tough insulating material, the bushing having a fiange to engage the plate on one side and a. plurality of integral fingers having bases at the end of the bushing away from the flange but extending toward the flange, the fingers having enlarged stepped ends forming shoulders to engage plates of different thickness, the finger being adapted to be forced inwardly as the bushing is forced into a hole in the plate but having resilience so as to snap back into looking position when the bushing is pushed into the plate against said flange.

FERDINAND KLUMIPP, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,483,213 Fahnestock Feb, 12, 1924 684,909 Cole Oct. 22,1901 Re. 13,529 Thoradarson Feb. 11, 1913 1,204,625 Wheelock Nov. 14, 1916 1,171,267 Smith Feb. 8, 1916 1,890,348 Weatherhead Dec. 6, 1932 

